Method of separating gas mixtures.



1. E. LILIENFELD.

METHOD OF SEP ARATING GAS MIXTURES. APPLICATION FILED ocr. 13'. 1911.

1 $63,428; Patented 960.7, 1915.

JULIUS EDGAR LILIENFELD, OF LEIPZIG', GERMANY.

MErHoIi or SEPARATING GAS MIXTURES.

Specification of Letters Patent.

Patented Dec. 7, 1915.

Application filed October 13, 1911. Serial No. 654,524. I

The present invention'relates to improvedmethods of separating gasmixtures, and consists in the steps and processes hereinaf ter'described and claimed.

Previous methods for separating the components of atmospheric air havedepended for their elfectiveness upon the use of the return currentprinciple and upon the employment of as efiective an insulation aspossible against the outside air. In these prior methods, air, or atleast a large portion thereof, is first liquefied and the oxygen thenrecovered from the liquefiedair by rectification. p

In my improved process, the gaseous component of air having the lowerboiling point is not liquefied and collected in such state, nor are anyintermediate liquid products collected; thus eliminating the labor whichis necessary in previous methods.

According to the present invention, the increase in entropy is reducedas far as possible by the practical method in carrying out the processof separation, andby such means a considerable saving in labor isobtained compared to the best exlsting devices; in fact greater than ifan accessof heat from outside-were entirely prevented.

The present process will be described with 1 reference to theaccompanying drawing, I

wherein the figure is a vertical sectional view of an apparatus forcarrying out the process.

Referring more particularly to the drawing, 1 indicates a casing,wherein, in accordance with the present invention, a constant pressureis maintained, which pressure is lower than that to which the gasmixture introduced, has been previously subjected. The casingconstitutes the chamberwithin which the gas mixture isintroduced andwherein the process is conducted, that constituent of the gas mixturehaving the higher boiling pointbeing precipitated to the bottom of thecasing, whence the same may overflow through a pipe 2 and into anevaporator 3 located beneath the casing 1.

g The caslng 1 is provided with a perforated partition 1, the samedividing the easing into upper and lower compartments, in the uppercompartment of which is located a 001i 9 in open communication at itsupper end w1th the interior of the compartment and under the. control ofa valve 8. The 0011 9 '1n the upper compartment above the part tion 1 isarranged to communicate with a e011 6 in-the lower compartment, and theC011 6 is arranged to communicate with the atmosphere. A coil 7. isfurther provided 1n the casing 1 for the circulation therethrough of anexternal cooling medium,

which may be a gas mixture similar to that of the mixture upon which theprocess is operating. 7 V

The gas mixture, having been pre-cooled under suitable pressure, isintroduced at the) lower end of the lower section of the coil 4 whichlatter is located in the evaporator 3,

drawn off in the gaseous state and conducted to storage tanks for use.

After passing through the lower section of the coil 4 the gas mixturethereupon ascends to the upper section, which is located in the bottomof the -casing 1 and is surrounded by the liquid constituent which, actsto further cool the gaseous mixture. Under the control of the valve 5the gaseous mixture is permitted to issue into the casing 1, and, as thepressure therein is lower than that to which the gas mixture has beenpreviously compressed, such gas mixture will be permitted to expand inthe casing and willthereby become still further cooled.v It is tobeunderstood-that the various steps in cooling the gas mixture are to beso arranged that after the mixture has issued into the casing 1 the samewill be cooled to a very low degree above that of liquefaction.

' 1n issuing past the valve 5, the gas mixture will risein the casing 1,and a portion thereof will be admitted through the perforated plate 1into the upper compartment of the'casing and thence into the coil 9, as-controlled by the valve 8. The coil 9, ibeing in communication with theatmosphere will permit a further cooling of the gas mixture byexpansion, and the portion so cooled will be led downwardly through thecoil 6'and assist in cooling the gas mixtures in the lower compartmentof the easing; It. is to be understood that the temperature of thatportion'of the mixture admitted to the coil 9 has been reduced, byexpansion to atmospheric pressure, to a degreelower than that of theconstituent element having the higher boiling point.

r The medium thus cooled and passed through the coil 6 will therefore bevery effective in condensing the constituent of the gas mixtures in thecasing 1, havingthe higher boiling point, which condensed mixture willbe precipitated to the bottom of the casing, and,

j as above explained, will overflow through i that of the finally thepipe 2 into the evaporator 3, from which the same is drawn off in thegaseous state.

The coil 6 is assisted in its action by a similar coil 7, arranged toreceive and circulate a cooling medium, whichmay be a gaseous mixture ofthe same constituent elements as that of the mixture subjected to theprocess, and which coollng medium is to be maintained at atemperaturehigher than expanded portion of thegas mixture.

It will be understood from the foregoing" that, in accordance with thepresent process,

the component having the higher boiling point is recoverable from thegas" mixture I rangement of parts without departing from without thenecessity for liquefying the entire mixture and without producing anyintermediate products.

It is obvious that those skilled in the art may vary the details ofconstruction and arthe spirit of my invention, and therefore I do notwish to be limited to such features except as maybe required by theclaims.

I claimz 1. The herein described method of separating two components ofa gaseous mixture, which consists in compressing and cooling themixture, then expanding the compressed and cooled mixture to a constantpressure within a chamber forfurther cooling the mixture to atemperature above that of liquefaction, then finally expanding a portionof the mixture to atmospheric pressure for cooling such portion to atemperature below the critical temperature of the gaseous componenthaving the higher boil-' ing point, then progressively subjectingsuccessive portions of the mixture at constant pressure in said chamberto the cooling action of such finally expanded portion of the mixture,and simultaneously subjecting the successive portions of the mixture atconstant pressure in said chamber to the action of a cooling mediumhaving an initial temperature higher than that of such finall expandedportion of the mixture.

2. The herein described method of separating two components of a gaseousmixture,

cooling action of such finally expanded portion of the mixture, andsimultaneously subjecting the successive portions of the mixture atconstant pressure in said chamber to the action of a cooling mediumhaving an initial temperature higher than that of such finallyexpanded'portion of the mixture.

In testimony, that I claim the foregoing as 1' my invention, I havesigned my name in,

presence of two witnesses, this 3d day of October 1911.

.DR. JULIUS EDGAR LILIENI'ELD.

Witnesses:

RUDOLPH FRICKE, MAX Pressman.

